Dialing In (Be)for(e) Flow Control - Page 2

Beginner and pro baristas share tips and tricks.
PIXIllate

#11: Post by PIXIllate »

Jeff wrote: The first couple minutes of http://www.youtube.com/watch?v=teSDDFta5G4 are a quick, high-level discussion of extraction and light roasts.

This video discusses a Scott Rao style Allonge which by John's own description is probably only possible on the Decent and LM machines. He does comment a bit later that for blooming shots (which are more what we are talking about here with long PI times) he uses a grind setting about 2 notches finer on his Niche. I don't know how one notch on a Niche compares to one notch on my Vario but it does get back to a point in my original post as one of the choices for a starting place. Dial in a 2:1 shot and then go a bit finer for PI flow control shots.

Is this perhaps what you were trying to describe?

Jeff

#12: Post by Jeff »

When I got my DE1, I was coming from 15 years with the same E61 HX and 10 years with the same grinder. I was lost. 196 F on my EricS group-head thermometer I knew was close to right for the coffees I buy. The "default" profile was 190 F, which wasn't anywhere near the 200-ish that roaster often quote. I started with 18 g in an 18 g basket. Picked a profile that wasn't too fancy. Stayed at "15+" on my grinder, what I had just pulled shots with. It wasn't good. Bumped the grinder up as I would have on the HX. It still wasn't good. Repeat a few times. Ok, try a different profile. Readjust the grind a few times. Try a different profile. Repeat for a pound of coffee and a sink full of shots.

In retrospect, I was changing too many things at once, too fast.

Finally I decided to pick one profile and stick with it. It probably took me 10 shots to learn how my grinder and machine were interacting. Another three or four to explore temperature and accept that while my old number was 196 F but my new number was 88-90 C. Now that I know how my grinder and machine behave for that general kind of profile, I can dial in grind and dose in 3-5 shots. That's a result of knowing my baseline and getting better at guessing if I'm off by a bump, or a mark or two, based on the flow and taste. Those changes have roughly the same impact for the "normal" profiles, no, short, or long PI.

I've got three bags of unknown, unlabeled coffee coming next week. I'll start at 16 g at "15" on my grinder for medium-light roasts, "14" for light, and "16" for medium, into an 18-g basket. I'll use a profile I like that has slow PI that's generally a few seconds past first drops. I'll see how they pull, shooting for 32-35 g in the cup, however long it takes, then taste and adjust grind, dose, and/or yield.

If I think I've got the grind and dose close but the PI doesn't get any drops, I'll probably lengthen it. If it's running out the bottom of the basket too soon, it's more likely that I prepped poorly or grind/dose is way off. If I switch to a 14 basket and down dose, then I'd shorten the PI inflow rate, but keep the time the same. Less basket volume and less grinds means I need less water for the same level of saturation.

If I've got any left and in feeling adventurous, I might try a very different profile. I know that, for example, a long PI and bloom will need a much finer grind than my current profile to keep pressure up / flow down during the "extraction" phase. I'd go two marks finer, as a guess, and repeat the dial-in, as I'm really making a shot a very different way.

Edit: In answer to your recent question, it was more that lighter roasts are often harder to extract well. This often leads to finer grind, higher temperate, more water, more contact time, or a combination. Even with "sane" profiles (blooming and allonge aren't in that category for me yet), the same principles apply. Cooler, coarser, shorter times tend to extract less. Early, low-pressure infusion and its length are levers you can pull once you're close with a flow-management device.

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mohninme
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#13: Post by mohninme »

As a norm, I will shoot for a traditional 9 bar, 25-30 sec shot at 198*F as a baseline and then tweak from there (most true for medium+ comfort blend type coffees). I know that lighter roasts will not meet my expectations with these parameters so I will generally grind finer and pull longer & hotter right off the hop unless the roaster supplies a recipe and then I will start with that as a baseline.
Michael

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Peppersass
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#14: Post by Peppersass »

Generally speaking, I start by trying to dial in with "traditional" shot parameters (1:2 ratio in 25-35 seconds.) That sets a sort of baseline. If I can't fully extract the coffee with reasonable variations of grind, dose, time, etc., or I'm not getting the promised origin flavors, or I want a more concentrated shot (Ristretto) but can't get one that isn't sour, I'll resort to flow control.

This is almost always due to the coffee being a light roast. I rarely find medium or darker roasts that can't be dialed in with some variation based on traditional shot parameters. Even light-medium roasts will usually extract well with some persistence. I do have an excellent grinder known for doing well with light roasts, so that's part of why this approach works for me.

Another factor for me is that my modified GS/3 AV has a gear pump, so I can ramp the pressure down after the peak in order to keep the flow rate relatively constant (i.e., keep the flow rate from rapidly increasing as the puck becomes more permeable.) This works well for medium-light and medium roasts, and even some light roasts, because it increases contact time and thus extraction. It's not good for dark roasts, which don't need more contact time (often just the opposite.)

There are coffees that are visibly light enough that I can be almost certain they can't be pulled well with traditional shot parameters, so I go right to flow profiling for those. Until today, I've been able to simulate Slayer preinfusion by reducing line pressure with the regulator and turning off the pump, but there are several problems with this that I won't go into. Though I've been doing that for years, today I completed installation of a "Jake Valve" with a switchable bypass solenoid, an arrangement that lets me exactly duplicate Slayer shots.

I start dialing in for flow profiling by setting my grinder much, much finer than I do for traditional shots. It's an area about halfway between the setting for traditional shots and the finest the grinder can go (usually more toward that end.) I like to preinfuse until the first drops show at the bottom of the basket, which is about the same time as the basket pressure reaches maximum. After the peak, the flow rate will slowly increase as the puck becomes more permeable. When it hits about 60 ml/min, I start ramping down the pump speed to keep the flow rate as constant as possible (for singles, which I prefer, I keep the flow rate at about 30 ml/min.)

If you're wondering how I know the flow rate, the Arduino microprocessor I use for flow profiling reports it in ml/min. I'm able to use that information to set the preinfusion flow rate rate and the pump speed as I ramp the shot down.

PIXIllate

#15: Post by PIXIllate »

Peppersass wrote:Generally speaking, I start by trying to dial in with "traditional" shot parameters (1:2 ratio in 25-35 seconds.) That sets a sort of baseline. If I can't fully extract the coffee with reasonable variations of grind, dose, time, etc., or I'm not getting the promised origin flavors, or I want a more concentrated shot (Ristretto) but can't get one that isn't sour, I'll resort to flow control.

This is almost always due to the coffee being a light roast. I rarely find medium or darker roasts that can't be dialed in with some variation based on traditional shot parameters. Even light-medium roasts will usually extract well with some persistence. I do have an excellent grinder known for doing well with light roasts, so that's part of why this approach works for me.
Thanks for all of the information. This is kind of what I've been finding. Aside from one coffee (49th Parallel's Epic Espresso) I have not bought anything described as light roast. In fact I was surprised when I compared these beans to the others from the same roaster, they didn't look any "lighter" to me. In every case I have tried the flow control I've lost flavor separation and dynamics (punch) and ended up with a muted but pleasant drink. They do not remind me of the shots I enjoy from a Cremina which seem to have the smoothness but still with the individual flavor notes.

What I'm wondering is when using medium to medium-dark beans what kind of profile timing/flow rate/first drop have people found to benefit these coffees? Additionally what general flavor profile do people get from this process? As it is I'm getting good shots with "what's on the bag" flavors with these medium roast coffees when not using the flow profile and just pulling at a standard 7ml/sec 9 bar peak pressure with the traditional e61 pre-infusion. Is it just too extreme to try a 15-20 second 1.5ml/sec PI with this level of roast? Would something shorter benefit the coffee while retaining the distinct flavors? I guess this gets back to what you were saying about not going to a flow profile unless you can't get notes your looking for in a traditional way.

Maybe (at least with the coffees I've tried so far) if it ain't broke........ Wouldn't be the first time I've made life unnecessarily complicated.

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another_jim
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#16: Post by another_jim »

Coming late to the discussion.

After two years with the Bianca, I've settled into this basic routine: I use 15 grams in a conventional double basket, and vary the grind to work the extraction. I let the shot preinfuse at 2 bar until I see the first drops, then ramp the pressure up to 9 bar until the flow is established, then throttle it over the rest of the shot to maintain a steady flow.

This means, that for very fine grinds, I may let it preinfuse at 2 bar for 20 seconds. Since a double boiler doesn't overheat, this is not a problem. Very rarely, a coffee requires a grind so fine or so coarse that I vary the dose to keep the shot timing reasonable, but this is rare.

If I had to give my bottom line assessment of flow control now, I would unhesitatingly say that IT IS ABOUT THE GRINDER. Having flow control lets you use the grinder at a very wide range of grind settings, and so find the right extraction level for each coffee, without needing to jump through any hoops on basket choice, dosing, and leveling.
Jim Schulman

pcrussell50

#17: Post by pcrussell50 »

another_jim wrote:Coming late to the discussion.

After two years with the Bianca, I've settled into this basic routine: I use 15 grams in a conventional double basket, and vary the grind to work the extraction. I let the shot preinfuse at 2 bar until I see the first drops, then ramp the pressure up to 9 bar until the flow is established, then throttle it over the rest of the shot to maintain a steady flow.

This means, that for very fine grinds, I may let it preinfuse at 2 bar for 20 seconds. Since a double boiler doesn't overheat, this is not a problem. Very rarely, a coffee requires a grind so fine or so coarse that I vary the dose to keep the shot timing reasonable, but this is rare.

If I had to give my bottom line assessment of flow control now, I would unhesitatingly say that IT IS ABOUT THE GRINDER. Having flow control lets you use the grinder at a very wide range of grind settings, and so find the right extraction level for each coffee, without needing to jump through any hoops on basket choice, dosing, and leveling.
Another seminal post by Jim.

I don't think I have had to vary the dose even to keep shot timing reasonable. I just vary the flow for this (and yes, that means sometimes I don't even hit 9 bar, or I stay at 9 bar longer than I had planned before throttling). Where I tend to vary the dose is for headspace. Super light roasts tend to require more mass to fill the basket and darker roasts, less so.

Basket choice... So true. I rarely use my fast flowing, high EY baskets like VST any more. They sit forlornly in the back of my drawer while I use high quality baskets with more traditional flow rates. @jim... Where I do use my old VST baskets is when I make a "quasi-brew" like you were describing in your Bianca review, using flow control. In that case the fast flowing, large hole area of the VST helps the throttled water drip through without having to be forced under pressure.

-Peter
LMWDP #553

PIXIllate

#18: Post by PIXIllate »

another_jim wrote:Coming late to the discussion.

After two years with the Bianca, I've settled into this basic routine: I use 15 grams in a conventional double basket, and vary the grind to work the extraction. I let the shot preinfuse at 2 bar until I see the first drops, then ramp the pressure up to 9 bar until the flow is established, then throttle it over the rest of the shot to maintain a steady flow.

This means, that for very fine grinds, I may let it preinfuse at 2 bar for 20 seconds. Since a double boiler doesn't overheat, this is not a problem. Very rarely, a coffee requires a grind so fine or so coarse that I vary the dose to keep the shot timing reasonable, but this is rare.

If I had to give my bottom line assessment of flow control now, I would unhesitatingly say that IT IS ABOUT THE GRINDER. Having flow control lets you use the grinder at a very wide range of grind settings, and so find the right extraction level for each coffee, without needing to jump through any hoops on basket choice, dosing, and leveling.
Could you offer any of your basic observations on how someone might use flow control to work with medium to medium/dark roasts in a way that would improve them compared to a standard e61 shot? I would be interested in methods for coffees in their sweet spot in terms of aging (1-2 weeks post roast) and for coffees that might have been ageing a bit too long (1-2 months in a normal freezer).

I don't vary my basket (18g VST) or dose (18-18.5g) or puck prep (grind, WDT with the same tool John uses, level, tamp).

So far I have tried doing a ~2bar PI until first drops (around 15-20 seconds with my typical grind setting) and then up to ~8-9 bar, immediately beginning to pull back the pressure for the remainder of the shot until I have my final weight in cup. With this method and the medium roast coffees (49th Parallel Middle and Old School) I have tried it with I've found that I'm getting a pleasant, homogenized flavor profile but none of the individual flavor notes like I do when I pull a straight version of the same shot. Does this sound correct or am I missing something?

pcrussell50

#19: Post by pcrussell50 »

PIXIllate wrote:With this method and the medium roast coffees (49th Parallel Middle and Old School) I have tried it with I've found that I'm getting a pleasant, homogenized flavor profile but none of the individual flavor notes like I do when I pull a straight version of the same shot. Does this sound correct or am I missing something?
Homogenization is to be expected versus stratification and separation, with long PI profiled shots. I get the same thing. Though with the lighter roasts I like, I don't feel like there are as many layers to homogenize or stratify anyway. If you want more top notch Jim-ism, read his first few posts here: Lelit Bianca Review Yes, it's a Bianca review. BUT almost all of the first few posts is about flow control and could be applied to any machine with that capability.

-Peter
LMWDP #553

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another_jim
Team HB

#20: Post by another_jim »

PIXIllate wrote:So far I have tried doing a ~2bar PI until first drops (around 15-20 seconds with my typical grind setting) and then up to ~8-9 bar, immediately beginning to pull back the pressure for the remainder of the shot until I have my final weight in cup. With this method and the medium roast coffees (49th Parallel Middle and Old School) I have tried it with I've found that I'm getting a pleasant, homogenized flavor profile but none of the individual flavor notes like I do when I pull a straight version of the same shot. Does this sound correct or am I missing something?
You are using the technique I describe. Your tasting notes indicate that the shots are over-extracted and too mild for your taste. You certainly want to grind coarser, and maybe drop the temp too. You should be going for a much shorter pre-infusion time. Other things to try are using a basket with less head space, or cranking up with initial water debit rate in the fist few seconds of the shot before the pressure starts climbing.
Jim Schulman